In recent years, existing information systems are developed by means of replacement. In this case, it is necessary to recognize, for example, specifications of the existing information systems, and programs of such system are being analyzed. There is Japanese Patent Application Laid-Open Publication No. 1997-26897 (PTL 1) as an example disclosing such technology. This publication describes a “program analysis apparatus for analyzing a source code of a computer program representing processing of data, the program analysis apparatus comprising: data information extraction means that extracts data information which is information indicating a structure of each piece of the data; and related information extraction means that extracts related information between the pieces of data with respect to a specified position of the source code on the basis of the source code and the data information (refer to claim 1 thereof).